This invention relates generally to control of water level in a watering trough, i.e., typically a cattle watering trough. More particularly, it concerns overcoming problems that arise with operation of fill control valves, due to freezing conditions.
A fill control valve for a watering trough is typically float controlled. As water fills into the trough via the control valve, a float rises to shut off water inflow via an inlet nipple at the valve. Conversely, when the water level drops, due to cattle drinking, water resumes inflow into the trough via the inlet nipple. It is found that, under freezing conditions, the inlet valve freezes up, and rising and lowering of the float becomes blocked. There is need for means enabling the float valve to operate normally during both above and below freezing conditions.